Frege's mistake lay in assuming an appealing theory about why people say what they do. He thought people believe sentences true because they believe what those sentences say. If so, then what someone thinks must exactly reflect what he would candidly assert. The theory appeals because it assumes a even simpler picture of thinking: it is the picture of thinking as talking to yourself, sotto voce.
Frege didn't invent this way of thinking about thinking, but he was the first to see how much must follow about thought and language if it is true. If we take it as analytic that beliefs have the functional role Frege assumes for them, we can define Frege Beliefs:
x believesF p =df x would believe ┌p┐ was true iff x understood ┌p┐
When contemporary philosophers talk about the "narrow", "notional", "opaque" or "internalist" sense of 'believes' they are talking about beliefF.
The theory extends to the other attitudes. Thus we have Frege Desires:
x wantsF that p = df x would want ┌p┐ to be true iff x understood ┌p┐ .
And supposing that what you understand are meanings, we can define Frege Meanings :
x understands the meaningF of ┌p┐ =df x would believe ┌p┐ was true iff x believedF p.
Frege called the meaningsF of sentences "thoughts" and the meaningsF of words "senses". As Michael Dummett tells us: "The sense is that part of the meaning of an expression which is relevant to the determination of the truth‑value of a sentence in which the expression occurs". We can specify the Frege Meaning or sense of a term thus:
x understands the meaningF of ┌a┐ =df x would believe ┌..a...┐ was true iff x believedF ...a...
After Frege, when philosophers spoke about "meanings" (and after Frege, they spoke of little else) they were always talking about meaningsF.
These equivalences don't count as ampliative definitions since meaningF and beliefF are defined reciprocally. A proper analysis would have to define either 'beliefF' or 'meaningF' in terms that did not assume the other. However, despite generations of effort, finding a non-circular analysis has proved problematic. It is one of those philosophical problems that has grown capital letters: it is " The Problem of Intentionality".
" Intentionality has to do with the directedness or aboutness of mental states — the fact that, for example, one's thinking is of or about something."
"Intentionality is the power of minds to be about, to represent, or to stand for, things, properties and states of affairs."
This makes "intentionality" sound like some sort of spooky power. But on reflection there seems nothing spooky, or particularly mentalistic, about "aboutness". You can throw your arm about your friend. The moon circles about the earth. The price of gas is about four bucks a gallon. Nothing mental here. These kinds of "aboutness" are just garden variety relations that one item can have to another.
What is distinctive about the "aboutness" that is supposed to characterize mental states is precisely that it is not a relation between a mind and what it thinks about. Relations require relata. You can't put your arm about something unless it exists. On the other hand it seems you can think "about something" even if it doesn't exist. Don't children have beliefs about Santa? They must. After all, they say things like “Santa is coming tonight." Then, too, ordinary "aboutness" relations are relations between things, no matter what you call them. A moon couldn't orbit about Hesperus without orbiting about Phosphorus; Hesperus is Phosphorus. But apparently you can think about Hesperus without thinking about Phosphorus; after all, someone could think 'Hesperus has a moon' was true but deny 'Phosphorus has a moon'.
So what's special about the aboutness of intentional states is that these states manage to be "about " things without actually being... well, about things. Which, come to think of it, is kind of spooky.
On the other hand if Intentionality comes down to these two semantic properties-- failures of existential generalization and substitutivity-- of propositional attitudes sentences, then it does seem that intentionality is a distinctive trait of sentences about the propositional attitudes; about what people believe and desire.
Or rather, intentionality is a distinctive trait of beliefsF and desiresF.
Philosophers generally acknowledge that there is a way of talking about the attitudes for which EG and substitution are valid. This non-Fregean way of talking is variously called the "wide", "de re", "relational", "externalist", "Millean" or "transparent" style. Call it "beliefT" ('T' for "transparent" ,of course).
BeliefT is not, in the technical sense, an intentional state. Of course, you have beliefsT about things, but this is just the boring, non-spooky, relational sense of 'about'. You can't have a beliefT about Hesperus that isn't also a beliefT about Phosphorus. And, no matter how much you may wish 'Santa will visit.' was true, you don't desireT that Santa will visit.
But, straightforward though it may be from a semantic point of view, most philosophers think that beliefF is both logically and psychologically prior to beliefT. They hold that beliefT must be analyzed in terms of beliefF, and that believingT presupposes believingF. They think that it is beliefsF that central to the explanation of behavior because Folk Psychology is Intentional.
I think this gets things entirely wrong. I'm an eliminativist about beliefsF; about "narrow", "opaque", "notional", "internalist" beliefs. I deny that there are intentional states. Intentionality is an artifact of the homuncular picture of thinking as talking to yourself.
Which is not to say that I am an eliminativist about the propositional attitudes or a skeptic about folk psychology. I believe in beliefsT and desiresT. And believe in folks. I don't think folk psychology is intentional.
Intentional psychology is a philosophers' chimera. The only behavior that beliefF and desireF can explain is linguistic behavior and there its explanations are circular. Philosophers miss this because the only kind of behavior philosophers ever talk about is linguistic behavior. Of course, no philosopher will come right out and say that all behavior is linguistic. We all know that people do more than talk. But if you ask a philosopher to explain some non-linguistic goings on, he will tell you that behavior can only be psychologically explained under the appropriate "intentional characterization". Which is a veiled way of conceding that intentional psychology doesn't really explain what people do but only what they believeF they are doing. This is only one of many circles which have kept philosophers spinning since Frege discovered meaningsF.
I hear the protest that if things were really as bad as I claim it ought to be easy to refute the Fregean view. I think it is. Here are three quick reductios of Intentional theory.
The Impossiblity of Communication
The Fregean story requires us to say that for two people to express the same beliefs by their words they must give their words the same meaningsF and that what people meanF by their words is manifested in their ways of deciding if sentences are true. But clearly we don't all meanF the same things by our words. Here is Jones. Jones says:
(J) "Smith has arthritis in his thigh".
Jones can't meanF the same thing by 'arthritis' as his doctor, because nothing could persuade his doctor to think (J) was true. So Jones and his Doctor must think different things when they contemplate (J). But that seems to show that when Jones and his doctor argue about the truth of (J) they are not really contradicting each other. They don't express the same thoughts by their words. Clearly such cases could be multiplied. This seems to show that people rarely communicate the same thoughts. Isn't this absurd?
The Impossiblity of Translation
As defined above beliefF does not require that one understand any particular language. We could for example say that a mono-lingual French man believesF that London is pretty if we had reason to believe that he would assert 'London is pretty” if he understood English. But can we ever have compelling reason to think that? Of course, Pierre might say, “Londres est belle” completely sincerely. But no matter what he says in French it seems possible that Pierre should learn English and then deny “London is pretty'” while still insisting "Londres est belle”. The upshot seems to be that we can't ever really say what Frenchmen believe. Isn't that absurd?
The Impossibility of Animal Thought
And what about creatures that don't speak a language? Here is Donald Davidson's dog Fido barking up a tree. Should we say that Fido believesF that there is a squirrel up a tree? If so, we are saying that Fido would endorse "There is a squirrel up the tree" if only he understood that sentence. But that seems a stretch. Consider that we would only count a human as properly understanding the sentence 'There is a squirrel up the tree' if he understood that it implies 'There is an animal up the tree', 'Something in the tree is alive.' &c. Do we really want to say Fido has all those beliefsF? Could a dog understand these words? Davidson thought not and so he concluded Fido can't think. Isn't this silly?
Alas, what these three cases really show is that one man's reductio is another's Deep Philosophical Problem. To banish intentionality will require a more patient attention to cases. In my next post on this theme, I will start with Kripke's puzzle.